Description

Parameters

exclude_disabled

Whether disabled functions should be excluded from the return value.

Return Values

Returns a multidimensional array containing a list of all defined
functions, both built-in (internal) and user-defined. The internal
functions will be accessible via $arr["internal"], and
the user defined ones using $arr["user"] (see example
below).

At least with PHP 4.2.3 on a GNU/Linux/Apache platform, get_defined_functions() returns user-defined functions as all-lower case strings regardless of how the functions are capitalized when they are defined.